Add code of conduct
Add code of conduct

This is the standard Contributor Covenant.

See-also: https://www.contributor-covenant.org/
Signed-off-by: Robbie Harwood <3f8631879978f4cea53bf1163760f1ac18f9cb08@redhat.com>

rhboot/efivar,rhinstaller/efivar,rhinstaller/efivar,rhboot/efivar